Theoretical And Quantum Chemistry Calculation Studies Of Nuclear Spin-induced Magneto-optical Effects

Nuclear magnetic resonance spectroscopy (NMR) and magnetic resonance imaging (MRI) are important techniques for molecular structure detection and clinical medical diagnosis. However, most NMR/MR1 studies follow the traditional concepts and methodology since its discovery. In 2006, Romalis and others reported for the first time the use of nuclear spin induced optical Faraday effect (NSOR) as an new optical NMR detecting method. Since them, the analytical theory and quantum chemistry calculations of NSOR have been extensively studied. In this dissertation, according to the experiment and the NSOR analytic formula of D. Pagliero et al. and Yao et al., we derived the ratio of nucleus NSOR(R) of chemically non-equivalent or different element nuclei in the same molecule. Based on the polarization theory such as Buckingham and Faraday effect theory, we studied the infrared region of nuclear spin induced magnetic circular dichroism in liquids. In addition, we theoretically discussed the liquid surface polarity Kerr effect induced by nuclear spin (NSMOKE), that including the polarization plane rotation and ellipticity. At last, we calculate the new Cotton-Mouton effect of the macrocyclic molecules with conjugate macrocycles.Chapter 1 mainly describes the basic knowledge of the nuclear spin magneto-optic effect, including the basic principle of nuclear magnetic resonance (NMR), polarizability, magneto optical effect and quantum chemistry. We summarizes the research background, the present situation of magneto-optic effect research and main content of this dissertation in this chapter.In chapter 2, based on D. Pagliero’s experiment and Yao’s NSOR analytical formula, we derived the thoretical expression of the ratios of R between chemically non-equivalent or different element nuclei in the same molecules. Similar chemical shift of traditional NMR spectrum, Vaara et al. recently proposed optical chemical shift in nuclear spin induced magnetic rotation (NSOR). In this chapter we theoretically researched this problem through comparison of NSOR magnitude between chemically non-equivalent or different element nuclei in the same molecule. First, the application of known semi-empirical NSOR theory is deduced from theoretical expression of the ratio R. Second, taking methanol, diethyl phosphite and 2-methyl benzothiazole as examples, calculate the ratios of the R, the calculation results consistent with the experimental results. Finally, based on these results, we discusse the important factors that affect R, and discusses how to identify different functional groups in the same molecule.Chapter 3 studies nuclear spin-induced magnetic circular dichroism (IR-NSCD) in the infrared region. Recently, the nuclear spin-induced optical rotation (NSOR) effect and nuclear spin induced magnetic circular dichroism (NSCD) in liquids were extensively studies and developed. So far, nuclear spin-induced magnetic circular dichroism (IR-NSCD) in the infrared region in liquid has not been explored. In this chapter, nuclear spin-induced magnetic circular dichroism in the infrared region was propsed and discussed theoretically. It was found that, due to the resonance vibration effect, nuclear spin-induced magnetic circular dichroism angle (IR-NSCD) in IR can be much more larger than nuclear spin-induced optical rotation (NSOR) angle in the visible light region, and nuclear spin-induced magnetic circular dichroism angle (IR-NSCD) can be measured through the optical rotation (NSOR) experiments. In liquids, IR-NSCD can automatically combine and give nuclear magnetic resonance (NMR) spectroscopy and infrared area circular dichroism spectra (IRCD) of nuclear spin prepolarized samples.In chapter 4, nuclear spin-induced polar magnetooptical Kerr effect (NSMOKE) is proposed and theoretically discussed. This effect consists in both a rotation of the polarization and the appearance of ellipticity, occurring when linearly polarized light is reflected from the surface of a nuclear spin polarized liquid with the magnetization normal to this surface. The NSMOKE effect can provide the NMR spectra from liquid surface and give the information of chemical composition, orientation, and intermolecular interactions of the surface molecules. By using infrared (IR) light, NSMOKE can simultaneously give both NMR spectra and IR spectra of surface molecules, which, in principle, can be developed to become a unique analytical tool for vapor/liquid interfaceIn chapter 5, quantum chemistry calculations have been used to study the new Cotton-Mouton effect (IBCM) proposed by Yao el at., which is induced by the crossed effect between the high dc magnetic field and nuclear magnetic moment in liquids. We use density functional theory to calculate the new IBCM effect for tetraoxaporphyrin (TOP2+), [18] annulene, coronene and perfluorocoronene. For these non-spherical molecules, the IBCM effect is dominated by the temperature-dependent term. The DFT calculations demonstrate that these molecules have large anisotropic frequency-dependent polarizabilities and nuclear magnetic shielding tensors.Especially, the IBCM effect can be resonantly enhanced when the wavelength of the incident light is close to the electronic transition of the macrocylic molecules.